I recently submitted a ticket for a client who was getting punches with a GPS accuracy of 970 meters. In my opinion, an error message would be more useful than a location that could be off > .6 miles.
Ideally, the threshold could be managed by a Client login. A simpler alternative would be to have the threshold set to a specified value in the app, perhaps 30 meters or so, and have the app generate an error message based on the threshold.
Thanks,
Ted